Chrome monoazo dyestuffs



i atenteci May 1,

CHROME MoNoA zo DYESTUFFS Guido Schetty, Basel, Switie'rland, assignol' to a J. R. Geigy A. G., Basel,;Switzerland; a Swiss company N 0 Drawing. Application September 1945i; Se liial7N0'. 48,151. In switzcrland septeniber' 19,

A great number of chromium containing azo dyestufis suitable, for dyeing wool in the aciddye-bath are known. They all have the characteristic that they contain groups giving rise to anions, particularly sulfonic acid groups. Upon this depends their solubility in water, which is essential if they are to be of use in textile-dyeing. They vary little from acidlevelling-dyestuffs for wool in respect of chromium content, but quite considerably as regards application, since they only give even, full and fast dyeings on wool inia strongly acid, usually st10ng-' ly; mineral acid, dyebath. The usual dyeing method forvchromium containing azo dyestuffs consists in boiling the woolfor several hours in a dyebath with 6-8% of sulfuric acid, calculatedon the, weight of wool. This considerably damages thewool fibres however, so that this method is notssuitable for dyeing the finer qualities. According to G, L. Royer, E. Millson, and: C. A. Amick (Journal of the Society of; Dyers and:

Colourists, 63, 212424 (1947)) damagerto: wool is: least on boiling in water; at acidities correspending to the isoelectric point of the'wool; Consequently aldyeing method which is to safeguard thefibres must use albath which has only aweak acidity; ranging from thatof acetic, to that; of: formic acid, and dyestuffs are required, which give; full; and even; dyeings under these. conditions. givesatisfactory results in the weakly acid-dyebath, most chromium-containing wool dyestuffs;- give only very uneven, weak and practically" Worthless dyeings with poor fastness properties by this method; However, sincesuch dyestuffs havewell known advantages, it would be a.' big. technical advance if they could be used to dye wool under conditions non-injurious to the fibres. According to Ender and Miiller (Melliands; Textilberichte, i9, 181, 2'72 (1938))- the striking: difference in the dyeing properties of, azo dye stuffs containing chromium and sulfonic acid groups in the weakly acid and in the strongly acid dyebath arises because, during dyeing, the: chromium atom as well as the sulfonic acid group. becomes bound to the wool-protein; With in-' creasing acidity of the dyebath, however, the aflinity of the chromium atom for the woolproteinfldecreases, while that of thesulfonic acid-*- groups increases, so that the nature of chromiumcontaining wool dyestuffs in the strongly mineral acids dyebath-Uapproaches' that: of the acidlevelling; dyestuffs, and even, fully developed dyeings are: obtained: From this explana'tio'rr it" follows}: that complexi chromium compounds of While many non-chrome wool dyestuffs? 7 Claims. (01. 260447) azo dyestuffs with no anionic groups cannot; be-

have like acid. levelling dyestuffs. Complexchromium compounds of monoazo dyestuffs which contain no ionic groups, such as carbox-yl,

sulfonic acidiand amino groups, but contain sub stituents usual in azo dyestuffs, e. g., halogen, alhyl, aliaoxy and nitro groups, have been: rei-' peatedl'y" described patent literature. As expected, they are insoluble in water and therefore of no direct use in the textile industry. A's they 1 are soluble in organic: solvents, for example in lower alcohols, they are used for colouring var .nishes.

The surprising discovery has now been made 1 that monoazo dyestuffs of the general formula A represents a benzene nucleus,

B represents the radical of a member selected from the" group'consisting of phenolic, naph tholic and" enol'ic coupling components; cou-' pling in o-position to thehydroxyl group, p

X represents a' metallizable group in o-positibrf to-the' azo group with the condition that any further constituents carried by A and'B must" be non-ionising, and g g g oneof the integers'l' and 2, the'm'ethyl'sulfoiie group being bound aromatically;

can be converted by. chroming methods: known per se into water-soluble chromium complexes which dye wool in'very even full and fast shades from the weakly acid-bath.

The chromable monoazo dyestuffs according v to theinvention' are thus characterised by the presence of one or two aromaticallys bound methylsulfone groups and by the absence of the acid, salt-forming groups:' containing sulphur or' carbon (so far as the carboxylugroup is not used ininetal-complexformation) usual in chromable monoazo dyestuffs.- The characteristic methyl sulfone 'group can not bereplacedin the monoazo dyestuffs used according to the inventionb'y another non-ionising: negative group introduced in.thersame -position, e. g.', thenitro group, with out to alarge: extent losing the valuable prop-' erties of the?chromium -containing final product. As-I far as isknown; the methylsulione roup has not, previously been used as asubstituent" in 0:0" dihydr'oxyazo, or o hydroxyo'carboxy chrome azo dyestuffs?at least not in o:o-dihy droxy or o-hydroxy' of-ma'rboxy monoazochroine dyestuffs. This becomes understandable,- whenitiis realised that the"corresponding chromium 3 free monoazo dyestuffs when after-chromed on wool give dyeings with only moderate fastness properties when wet.

It is all the more surprising that the new complex chromium compounds give dyeings on wool having good wet-fastness properties, especially bearing in mind the opinion of Ender and Muller (loc. cit.) according to which sulfonic acid groups are necessary for binding the dyestuff to the wool proteins.

The new chromium-complex dyestuffs are excellently suited for dyeing wool from a weakly acid, for example, 2% acetic or up to 4% formic acid dyebath (the percent acid is calculated on the weight of material to be dyed) since they are readily soluble in water and do not precipitate even from a weakly acid aqueous medium. Naturally, the additives usual in wool-dyeing can be added to the dyebath, such as sodium sulfate, ammonium sulfate, sodium pyrophosphate or condensation products of fatty alcohols with ethylene oxide, guanamine sulfonic acids with high molecular alkyl radicals and the like. The new products draw well on Wool, level well and yield fully developed, very even shades. Another important property is that they dye mixtures of loose wools of diflerent origins very uniformly. Thick piece-goods are generally very well penetrated, an advantage which made the brownish chromium complex dyestuffs containing sulfonic acid groups so valuable in spite of the damage done to the wool.

The monazo dyestufis serving as starting material for the present invention are obtained from methylsulfone substituted diazo or coupling components, i. e., the methylsulfone group can be either in the diazo or in the coupling component or in both, their maximum permissible number being two, however. As further substituents not taking part in the metallising process-may be named: halogen, alkyl, alkoxy, acylamino, nitro, carboxylic acid-amido groups and the like.

Methylsulfone substituted dyestufi components are obtained by known methods by methylating the corresponding sulfinic acids, e. g., vith dimethyl sulfate, or by oxidising methylthicphenyl ether, e. g., with hydrogen peroxide. Thus the valuable methylsulfonyl-o-amino-phenols of the present invention may be prepared from o-nitrochlorobenzene'sulfonyl chlorides by first mildly reducing with sodium sulfiteto the corresponding sulfinic acids, methylating these, then replacing the chlorine atom by the hydroxyl group with caustic alkali and next converting the nitro group to the amino group, for example, by reduction with sodium sulfide. Ortho-alkoxy compounds are obtained analogously through the reaction of the chlorine atom with alcoholates. Ortho-carboxy compounds are derived from o-nitro -methylmethylsulfonyl benzenes by oxidation with permanganate and the like. The following further examples of such compounds may be named: l-hydroxy, l-methoxy-, l-ethoxy-, l-chloro-, 1-brom0-, and l-carboxy-2-amino-4-methylsulfonyl-benzene, 1hydroxy-2-amino-4-methyl sulfonyl-fi-chlorobenzene, 4-chloro-2-amino-lhydroxy 6 methylsulfonylbenzene, 4-nitro-2- amino l hydroxy 6 methylsulfonyl-benzene, 2 amino l hydroxy-4:G-di-(methylsulfonyl) benzene. Methylsulfone substituted coupling components are obtainable, for example, from methylsulfonylaminobenzenes by condensing these with diketene or B-keto-carboxylic acid esters to form. the corresponding aceto-acetic acid anilides, by converting the amino group by known methods to the hydrazino group and con densing with fi-keto-carboxylic acid esters to form l-aryl--pyrazolones, or from the O-acylsulfonyl compounds of the naphtholsulfonic acids via the sulfonyl chloride and sulfinic acids by methylation followed by saponification of the O-acyl group. Particularly suitable coupling components are 1-hydroxy-5-methylsulfonylnaphthalene, Z-hydroxy-6-methylsulfonyl-naphthalene, 1-(3' -methylsulfonylphenyl) -3-methyl 5-pyrazolone, 1 (4 methylsulfonylphenyl) -3- methyl-5-pyrazolone. Apart from the diazo and coupling components named, which are partly new, naturally there may also be employed the diazo and coupling components free of sulfonic acid groups and with a single carboxyl group in ortho-position to the diazo group as used up till now in chrome dyestufis, i. e., especially o-aminophenols and aceto-acetic acid arylides, pyrazolones, hydroxyquinolines, phenols and naphthols which may all contain further non-ionising substituents. Monaco dyestuffs derived from diazotised monomethylsulfonyl-o-aminophenols and compounds of the benzene, naphthalene and pyrazolone series coupling in the neighbouring position to the hydroxyl group and containing no or only one methylsulfone group are very suitable for the new rocesses.

Particularly valuable are dyestuffs produced from diazotised di-(methylsulfonyl)-o-aminophenols and the coupling components without a methylsulfonyl group mentioned. In contrast to o o -dihydroxyazcand o-hydroxy-o -carboxyazo dyestuiis, the o-amino-o-hydroxyazo dyestuffs containing methylsulfonyl groups give only unusable, difficultly soluble'chromium compounds. The complex chromium compounds of the o- -hydroxyocarboxyazo dyestuifs according to the invention are in general somewhat less fast under wet conditions than those of the o:o'-dihydroxyazo dyestuffs.

As examples of o:o'-disubstituted azo dyestufis, which can be converted into o:o'-dihydroxyor o-hydroxy-of-carboxy azo. dyestulfs under the conditions of the chroming reaction may be mentioned: o-chloro, o-bromo-, o-methoxy-, o-ethoXy-, o-carbomethoxy-, o-carbethoXy-, o- (p'-toluenesulfonyl-hydroxy) o-carboxylic acidmethyl esterand o-carboxylic acid-ethyl estero'-hydroxy azo dyestufis.

The monoazo dyestuffs serving as starting material for the present manufacture can be converted into water-soluble chromium compounds by known chroming methods. Particularly suitable are those chroming methods employing an alkaline aqueous medium, for example, those using glycerol-alkali chromite. Another chroming method excellently adapted for the present manufacture is that carried out in a practically neutral medium with complex chromium compounds of o-hydroxy-carboxylic acids of the benzene series (U. S. P. 2,417,735). Chroming can be effected at a raised temperature in either an open or a closed vessel. Chroming with trivalent chromium salts is best carried out in organic solvents, for example, in lower alcohols. After the conversion has taken place, alkaline reaction must be ensured or the reaction product must be digested with an alkali lye or with substances with an alkaline reaction, for example, soda, sodium phosphate or sodium pyrophosphate.

A process for dyeing animals fibres with complex chromium compounds of ozo-dihydroxy azo dyestuifs containing no sulfonic acid and sulfamide groups is already known. According to it the water-insoluble complex chromium compounds are applied in the form of a suspension in a neutral toweakly alkaline medium. In contrast, the process of the present invention uses the conventional method of dyeing wool from an aqueous solution and an acid bath. Furthermore, the new dyestuffs according to the invention are distinguished by much better levelling power,

Finally, a process for the manufacture of water-soluble, chromium-containing dyestuffs'by chroming chrome dyestuiis free from sulfonic aeidgroups has been described (U. S. P. 2,417,735),

,includingthe chroming of dyestufis from diazotised 4-nitro-2-aminophenol and I-phenyI-B- rhethyl-d-pyrazolone with complex chromium compounds of' aromatic o-hydroxycarboxylic acids. However, this chroming reaction as can be seen from the patent specification in question, does not proceed uniformly, since not inconsiderable quantities of water insoluble by-products are formed. In addition, this special chroming process is fairly expensive because of the use of complex chromium compounds of aromatic ohydroxy-carboxylic acids containing sulfonic acid groups. In contrast, by chroming the dyestuffs originally defined herein complex chromiumcompounds which are usable in their entirety for wool-dyeing are obtained, i. -e., a considerably better yield of dyestufi; furthermore, cheaper methods, of chroming can be used.

The new dyestuffs are suitable not only for the dyeing of wool but also for dyeing synthetic fibres analogous to wool from super-polyamides and super-polyurethanes, casein fibres, etc. They are also suitable for dyeing silk and leather, especially glac leather.

The following examples illustrate the invention, without limiting it. The parts are by weight, unless otherwise stated, and the temperatures are in degrees centigrade. The-relationship of parts by weight to parts by volume is that of kilograms to litres. Example 1 COCHa lOsNH 18.7 parts of Z-amino-l-hydroxybenzene-imethylsulfone are dissolved in 150' parts of hot water with 17 parts of concentrated hydrochloric acid,.cooled to 5 and diazotised with a solution of sodium nitrite (corresponding to 6;9 parts). The diazonium compound partly precipitates as clay coloured crystals. The reaction mixture is made neutralby adding sodium bicarbonate and the suspension poured into a solution of 18.1 parts oi the anilide of aceto-acetic acid, 10.5 parts by soaorn.

volume of 10 N caustic soda lye and 1 2;parts of can be made as follows: 1 mol of 1-chloro-2 nitrobenlzeneq-methylsulfone (iBr-it. Pat. 467,549) is stirred with 2 mole of dilute caustic soda lye for aiewhours-at the boilingpoint. The"2-nitro1- hydroxybenzene-4-methyl-sulfone is then reduced by 'theusual methods, e. g., by heating with so diu sulfide so Example 2 coon S OmCHz 21.5 parts of 2-amino-benzoic acid-4-methylsulfone are dissolvedin 100' parts'of water with 6 parts of anhydrous soda. A solution of 6.9 parts of sodium nitrite is added, the whole cooled to 5 and then stirred into a mixture of 30 parts conc. hydrochloric acid, 100 parts water and 30 parts ice. N ex;t sodium bicarconate is added until the n ac i n is fa ntl blue t Congo p p r and; the

, djazoni-um solutionpoured into a solution of 10.2 parts of 3.-methyl-5'-pyaz o1one and 25 parts of anhx roussoda in 200 parts f W ter. After. counlins is. compl te. the dy stuf s s l d by addcommonsalt, stirred with 300 parts of water and boiled for 2 -3 hourswith 200 parts of, ammoni m chromo-salicylate (corr pondin to 7.5: parts of chromic oxide). Next the dark" yellow solution is evaporated to, dryn ss. T d e ufif scobtained; is a clay coloured powder which dyes:

wool in very level yellow, li ht-fast shades irom: ai-ba-th. madeacid; with. or anic: acids.

Z-amino-henzoic acid-d-methylsulfone can. be I prepared as follows: L-methylbenzene-4-methyl:- sulfcne; (Otto, B; 18;- 161, (1,885)), is nitratedv to 2z=nitrorlemethylbenzener4-methy1sulfone (M. Rt; 1181-119? recrystallised, from glacial acetic acid) the m'tro, compound isoxidised Withpotase sium permanganate to, 2rnitro-benzoic, acid-4- methylsulfone (M. Pt... 210-211, recrystallised from water) which is. thenreduced by the usual methods, e..g., with ironrfilingsand acetic" acid in,wa.;ter.-' (M.;Pt. 243, recrystallised from: wateri) 26.5 parts of 2-amino-1-hydroxybenzene-4:6-- di-methylsulfone are -dissolvedin 150 parts of hot water with 6 parts of anhydrous soda. The solution is cooled to 0, 30 parts of concentrated hydrochloric acid are added and diazotisation carried out as usual. A suspensionof yellow crystals. is obtained. The excess hydrochloric acid is neutralised by adding sodium bicarbonate and the mixture is poured at, 5" into a solution of 18.4

parts of. .1-pheny1- 3r-rnethyl-5-pyrazolone and. 20 parts anhydrous soda in 200 parts of water. diterformationoi the dyestuff'is complete it"is salted out andseparated'by filtration. It is then pasted up with 500 parts of water, 200 parts of nsolution of ammonium ,chromo-salicylate (corresmndma o. 51%?125 h o i x d added n the who eheat d p' .bq n x e a ew 11. 15

.An orange solution is obtained containing a partly separated crystalline chromium complex. The separation of the latter is made complete by adding common salt. After filtering and drying, a brownish-orange powder is obtained which dyes wool from a bath made acid with formic acid in full orange shades which are very uniform and fast to light.

The new diazo component can be prepared as follows: 1-hydroxybenzene-4 G-di-methylsulfone (Heppenstall and Smiles, Journal Chem. Soc. 1904 (1938)) is nitrated and then reduced.

Example 4 O l N 22.2 parts of 4-chloro-2-amino-1-hydroxyben- :zene-G-methylsulfone are stirred with 25 parts of concentrated hydrochloric acid in 150 parts of hot water, cooled to -3 and then diazotised with 6.9 parts of sodium nitrate in 20 parts of water. .After completed diazotisation the reaction mixture is neutralised with sodium bicarbonate and the suspension of the diazonium compound is poured into a solution cooled to. 0 of 10.2 parts of 3-methyl-5-pyrazolo-ne and 12 parts anhydrous soda in 100 parts water. Stirring is continued at 3-5 until dyestuff formation is complete, then, after warming to 80 and allowing to cool, the precipitated, crystalline dyestuff is filtered off. It is chromed by stirring for a few hours in 500 parts of water with 200 parts of ammonium chromo-salicylate (corresponding to 7.6 parts of chromium oxide) and the chromiumcontaining dyestuff is then separated from the orange solution which develops by adding common salt. After filtering off and drying, the dyestuif is an orange powder dyeing wool from a bath containing 2-4% formic acid in pure,

orange-red shades which are very fast to light.

The dyeings have very good wet-fastness properties and are verylevel.

4-chlo-ro-2-amino-1-hydroxybenzene-6 methylsulfone can be made as follows: 1:4-dichlorobenzene-Z-methylsulfone is heated I for a few hours at 180-190 with 2 mol of 5% caustic potash lye; the l.- chloro-1-hydroxybenzene-6-methylsulfone so obtained is nitrated to 4-ch1oro-2- nitro-l-hydroxybenzene-6-methylsulfone which is reduced with sodium sulfide.

' Example 5 water with 200 parts of a solution of ammonium chromo salicylate (corresponding to 7.6 parts of chromic oxide). A brownish-red solution results out of which part of the chromium complex separates as a black precipitate. While the reaction mixture is still hot, 25%,of its volume of common salt is added. After cooling, the precipitated complex is filtered off and dried. A red powder is obtained. To increase solubility it is mixed with 15% of its weight of sodium pyrophosphate and 10% of a guanamine-sulfonic acid with a high-molecular alkyl radical (see Brit. Pat. No. 561,548). The dyestufi dissolves readily in hot water. It dyes woolfrom a bath made acid with acetic or formic acid in clear, scarlet red shades which are very fast to light. The dyeings are also distinguished by a high degree of evenness and by good wet fastness properties.

If instead of the above dyestuff there is used 35.9 parts of the dyestuif from Z-amino-l-hy- .droxybenzene-4-methylsulfone 2:4 dihydroxy quinoline, having the formula SOaOH then a chromium complex is obtained which dyes wool in somewhat duller and bluer shades of red. However, hese dyeings have still better wet-fastness properties.

22.2 parts of 6-chloro-2-amino-l-hydroxybenzene-l-methylsulfone are dissolved in 200 parts of hot water with 18 parts of concentrated hydrochloric acid, cooled to 5 and diazotised with 6.9 parts of sodium nitrite in 20 parts of water. The diazonium compound precipitates out in the form of minute yellow crystals. Sodium bicarbonate is added until the reaction to Congo paper is neutral and the whole is then poured into a solution of 17.3 parts of 1-hydroxy-3-acetylaminoi-methylbenzene, 12 parts of anhydrous soda, 4.8 parts sodium hydroxide and 15 parts of pyridine in parts of water. The reaction mixture is stirred for 12 hours at 0-3 and 24 hours at 20, then warmed to 70 and common salt added. -The dyestuff precipitates out in powder form and is filtered off hot. For conversion to the chromium complex it is stirred for a few hours, while boiling, with a solution of 550 parts of ammonium chromo-salicyiate (corresponding to 7.6 parts of chromic oxide) and the chromed dyestuff then separated by adding common salt. On separation the chromed dyestuff is a reddish-brown powder, whose solubility may with advantage be increased by mixing in sodium pyrophosphate. From a bath made acid with acetic or formic acid it dyes wool in reddishbrown shades which are very even and fast to light. The dyeings exhibit particularly good penetration.

6 chloro-2-amino-1-hydroxybenzene-4-methylsuifone can be made as follows: 1:2-dichlorobenzene-4-methylsulfone (C. 1939 I, 250) is heated at ISO- with 10% caustic soda lye,

Example 7 18.7 parts of 2-amino-1-hydroxybenzene-4- methylsulfone are diazotised and coupled, after neutralisation with sodium bicarbonate, at 20 with a solution of 12.8 parts of 3*:4-dimethyl-1- hydroxybenzene. together with 1 5 parts of anhydrous soda, 412 parts of'sodium hydroxide (as a 30% solution) and 20 parts of pyridine in 200 parts of water. The dyestuff, which precipitates almost completely, is filtered off, pasted up with 600 parts of water and then boiled under reflux for 5 hours with 200 parts of a solution of ammonium chromo-sal'icylate (corresponding to 7.6 parts of chromic oxide). Next. the complex is salted out with 210 parts'of common salt, filtered ofl" after cooling, dried and mixed with 17 parts of sodium pyrophosphate. The new dyestufi,

' which is a brown powder, dyes wool from an acid bath (organic acid) in fullred-brown shades of goodevenness and possessing very good. wetfastness properties as well as good fastness to light.

A similar complex compound is-obtained if. the azo dyestufi is heated. to boiling with 100' parts offpotassium chromite-glycerolsolution (.see, e. g.,

. British Pat..186;635), correspondingto 7 partsof chromic oxide, for a few hours. and the chromed dyestufif filtered. off; after first diluting with water.

If the 2-amino-l-hydroxybenzene-4-methylsulfone in the above. example is replaced by 22.2 parts of 6-chloro-2-amino-l-hydroxybenzenelmethyl'sulfone, then a browner, duller dyestufi which otherwise has. similar properties is obtained.

Example 8 N==l7l rut-o ocH,

40 parts of the dyestuff obtained by coupling 18.7" parts of diazotised 2-amino-1-hydroxybenzene'-4.-methylsulfone with 21.1 parts of l-acetylami'n'o-7 hydroxynaphthalene are heated to boiling under reflux in 500 parts; of water with 200 partsof a solution of ammonium oxalato-aminochromate (corresponding to 7.6 parts of chromic oxide)" until formation of the complex is finished.

The complex separates out to a large extent dur- 10 are used instead of" the above dyestufi'" there is produced a dyestufi of the formula:

' which is even more suitable for'dyeing wool from .in 130 parts of chromic fluoride solution (corresponding to 7.6 parts of chromic oxide). Next 27.2 parts of 21.4% ammonia are allowed to flow in slowly under the surface of. the solution. over a period of 25 minutes. forms which: is diluted to 200 parts with water.

5-nitro-2-amino-l-hydroxybenzene-4-methylsulfone is prepared as follows: 1-hydroxy-2-- aminobenzene-4-methyl-sulfone is converted to the corresponding benzoxazolone-methyl-sulfone (M. Pt. 218-220, recrystallised from water) by treatment with phosgene in an alkaline medium. This compound is nitrated' to-nitro-benzoxazolone-methylsulfbne (M. Pt. 265-267", recrystallised from water) which is hydrolysed to give the desired product by treatment with warm, dilute caustic soda solution; The product, recrystallised from water, has a M. Pt. of 236 (decomposition occurs on melting).

Example 9 341 parts of the dyestufi' obtained by coupling 1 18.7 parts of diazotised 2-amino-1-hydroxybenzene-4-methyl-sulfone with 15.1 parts of 2- hydroxynaphthalene' are chromed in the manner described in Example 7. After chroming is complete, separation of the dyestuff, which has already commenced is completed by the addition of common salt. The precipitated dyestuff is filtered ofl and dried and the violet-brown powder so obtained is mixed with sodium pyrophosphate and with a guanamine sulfonic acid containing a high molecular alkyl residue (see Brit. Patent 561,548) to increase the solubility and levelling power of the. dyestuff. It dyes wool and nylon from a neutral bath in level, brownish-violet shades of outstanding fastness to light. The wool dyeings have also very good fastness properties" towards laundering, stoving and a1- kaline treatment.

A dyestuff with similar properties is obtained when a corresponding amount of the. dyestuif from" 26.1 or 21.5- parts of 2-amino-1-methoxy (or -ethoxy)-benzene-4-methylsulfone respec- An apple-green solution.

OCH; OH

are heated in an autoclave for 10 hours with 600 parts of alcohol and 160 parts of aqueous chromium formate solution (corresponding to 8 parts of chromic oxide) containing 25 parts of 85% formic acid. The alcohol is then distilled off, the residue stirred up with water, filtered, dried and mixed with sodium pyrophosphate or anhydrous soda.

2'-amino-1-methoxy (or -ethoxy)-benzene- 4-methylsulfone can be prepared as follows: 1- chloro-2-nitrobenzene-4-methylsulfone is heated in benzene or chlorobenz ene with an equivalent amount of sodium methylate or ethylate in methyl alcohol or ethyl alcohol until the chlorine atom has been exchanged for the alkoxy group. The 1-methoxy-2-nitrobenzene4-methylsulfone (M. Pt. 147-148") or the corresponding ethoxy compound (M. Pt. 135) so obtained is then reduced.

Example 10 OH .I

NO N=N SO: 8H3

23.2 parts of 6-nitro-2-amino-1-hydroxy benzene-4-methylsulfone are dissolved in 150 parts of water with 15 parts by volume of 10 N caustic soda lye. To this solution is added a solution of 6.9 parts of sodium nitrite in parts of water, and the mixture is then allowed to flow into 100 parts of water, parts ice and parts concentrated hydrochloric acid. After completion of diazotisation the reaction mixture is neutralised with sodium bicarbonate and the orange suspension of the diazonium compound is poured at 0.5 into a solution of 11.3 parts of '1- methyl-phenol, 30 parts of pyridine, 15 parts of anhydrous soda and 4.2 parts of sodium hydroxide in 300 parts water. Stirring is continued, while cooling with ice, until coupling is complete then, after warming to 70, the dyestufi is precipitated by the addition of common salt, filtered oil and washed with 20% brine. While still wet the dyestuff is stirred up with 1000 parts of water, 200 parts of a solution of ammonium-oxalatoammino-chromate, are added (corresponding to 7.6 parts of chromic oxide) and the whole heated to boiling for 48 hours, A brownish-black, finely crystalline precipitate forms which is filtered hot, washed with cold water, dried and then mixed with sodium pyrophosphate and a dispersing agent as described hereinbefore. The new chromium-containing dyestuff which is a brown powder, dyes wool from the neutral or weakly acid (acetic acid) bath in brown shades which are fast to milling, laundering and seawater. Non-homogeneous mixtures of loose wool are dyed very uniformly.

If this dyestufi is chromed with sodium: chr0:-

mite by methods known per se, then a complex compound is produced which dyes wool considerably redder. If ammonium chromo-salicylate is used, then the dyestuff formed gives dyeings which are somewhat greener and whose fastness to light is somewhat less.

6 nitro-Z-amino-l-hydroxybenzene-4-methylsulfone is made as follows: l-hydroxy-Z-aminobenzenel-methylsulfone is dissolved in sulfuric acid and then nitrated at 0 with a mixture of equal parts of nitric and sulfuric acids. Melting point, recrystallised from acetic, acid, 204-206".

Example 11 GHQ-s0 N=N NHoocrn dyestuff is a grey powder which dyes wool from an acid bath (organic acid) in full, grey shades having a good colour in artificial light. The dyeing are outstandingly level and are very fast to laundering and to sea-water.

If ammonium chromo-salicylate in the above example is replaced by a solution of ammoniumaxalato-ammino-chromate then the dyestuff obtained is excellently suited to dyeing wool in a neutral or weakly acid (acetic acid) bath.

Emample 12 The chromium-containing dyestufi is a brown powder which dyes wool from a bath made acid with acetic or formic acid in full reddish-brown shades which are very uniform and fast to light;

3;'7..2;'p arts of' the dyestuff obtained by coupling 18.7 parts of diazotised z-amino-l-hydroxybenzenel-methylsulfone with 18.3 parts of l-phenyl- 3-methyl-5-pyrazolone are chromed exactly as described in Example 3. The chromium-containing dyestuff separates during chroming in the form of fine crystals. It is filtered ofi, dried and mixed with sodium phosphate, soda or sodium pyrophosphate. It is an orange powder which dyes wool from the acid bath (acetic acid) in clear, orange, very uniform shades of very good fastness to light. The dyeings are very fast to laundering and sea-water.

Similar dyestufis are obtained if instead of phenyl-methyl-pyrazolone there are used 21.9 parts of 1-(3'-ch1oro-pheny1)-3-methyl-5-pyrazolone or 19.8 parts of l-(4-methyl-phenyl -3- methyI-S-pyrazolone.

The following table containsa list of further I4 2. The complex chromium compound of a monoazo, dyestuif having the formula OH OH I OFCHy H 4. The complex chromium compound of a monoazo dyestuff having the formula OH OH ACT-CH HN diazo and coupling components which can be used to produce chromium-containing dyestuifs ac- L cording to the invention.

- Colour of the Cr N o, Diazo Component Coupling Component complex on wool 3-methyl-5-pyrazolone orange. 1-hydroxy-3-acetylamino-4-methylbenzene reddish brown. 1-naphthol-5-methylsulfone violet. 2-naphthol-G-methylsulione reddish violet. 1-1(3-methylsu1iony1)-phenyl-3-methyl-5-pyraz0- orange.

one. 5a do 1-carbomethoxyamino-7-hydroxy-naphthalene greenish grey. 6 do v. 1-1(4-methylsulfonyl)-phenyl-3-methyl-5-pyrazoorange.

one. 7 4-111tro-2-amino-1-hydroxybenzene do Do. 8 5-nitro-2-amiuo-1-hydroxybenzene do bluish red. '9 5-nitro-2-amino-l-hydroxybenzene-4-methylsulfone. 3-methyl-5-pyrazolone scarlet. 10. do l-phenyl-3-methyl-5-pyrazolone Do. 11 do 3:4-d1methyl-phenol brownish violet.

' ydroxybenzcn "Dido brown.

l-Hydrox 3-acetylammoi-methylbenzene. reddishbtown. l-Hydroxy Z-acetylamino-4-methylbenzeneolive brown. 1-Hydroxy-4-methy1benzene brown. do Z-Hydroxynaphthalene violet brown.

2-amino-1-hydroxybenzene-4 6-b1s-met do Do. 2-aminobenzoic acid-4-methylsulfone brownish red. do etyl Xy-napht violet brown. do 1-phenyl-3 methyl-fi-pyrazolone reddish yellow.

What I claim is: The g zfigi gg f gfig a fgfig of a 5. The complex chromium compound of. a OIIOZJZO m y g 0 monoazo dyestufi havmg the formula wherein A represents a benzene nucleus,

B represents the radical of a member selected from the group consisting of phenolic, naphtholic and enolic coupling components, and

15 16 6. The complex chromium compound of a monoazo dyestufi having the formula REFERENCES CITED OH The following references are of record in the file of this patent: f- 5 UNITED STATES PATENTS Number Name Date \N/ 1,718,882 Schwenk et a1 June 25, 1929 2,228,303 Fischer Jan. 14, 1941 2,391,180 McNally et a1. Dec. 18, 1945 2,432,403 Felix et a1 Dec. 9, 1947 OTHER REFERENCES I '7. The complex chromium-compound of a, Sus: Ann. der Chem. V. 556 (1944) D- 0, monoazo dyestuff having the formula 15 6 P s- OH on SOIOHZ EN 20 GUIDO SCHETTY. 

5. THE COMPLEX CHROMIUM COMPOUND OF A MONOAZO DYESTUFF HAVING THE FORMULA 